The current situation

The systems we rely on to manage our waste are rooted in the Victoria-era and are increasingly struggling to cope with modern demands. The first septic tank was invented in France around 1860 by Jean-Louis Mouras, who later patented his design as the “Mouras Automatic Scavenger” in 1881. Around the same time, between 1859 and 1865, civil engineer Sir Joseph Bazalgette designed the modern municipal sewer system in London. While these 19th century inventions were revolutionary for their time, they are no longer meeting the expectations of people or the needs of the environment.

Today, around 1 million homes in the UK are not connected to mains sewers and instead rely on septic tanks to manage their waste. There is a common misconception that these tanks fully treat the waste they collect. In reality, they do not, which results in harmful pathogens and excess nutrients, such as phosphorus and nitrogen, being released into the natural environment. These nutrient releases can cause significant ecological damage, particularly when they reach local waterways, driving algae blooms that deprive rivers of much needed oxygen.

The situation is equally challenging for those connected to the mains. The sprawling Victorian sewer network was designed with overflow mechanisms that are now activated far too frequently. During periods of heavy rainfall, these combined sewers regularly discharge untreated waste directly into rivers and coastlines, creating a biodiversity nightmare. In 2025 alone, England and Wales recorded an astounding 386,466 wastewater discharge events into waterways, lasting a cumulative 2.65 million hours.

Compounding the issues of nutrient pollution and overflowing sewers is a growing crisis of water scarcity. Every single day, we flush 2.4 billion litres of clean drinking water down the toilet. This level of waste is unimaginable, especially in the context of the severe droughts that have affected the UK throughout 2026. Experts warn that we need to reduce our overall water usage by 5 billion litres a day—of which almost half is currently lost to toilet flushing—or we face a severe water shortfall by the year 2055. Addressing the interconnected issues of nutrient release from septic tanks, overflowing sewers, and water scarcity is now an urgent environmental imperative.

Through the Reinvent the Toilet Challenge, the Gates Foundation and its partners have developed over 25 breakthrough processing components and technologies, with solutions in use in communities around the world, and available for commercialization by product and sanitation service companies. These technologies are at the forefront of a growing movement to rapidly improve sanitation while creating new, profitable sanitation markets that advance progress toward the global water and sanitation targets outlined in the United Nations Sustainable Development Goals.

The high standards of reinvented toilet technologies are encapsulated in ISO 30500, a new non-sewered sanitation system ISO standard released in 2025. Key features of the ISO standard include requirements for outputs from systems to be pathogen-free, with very high levels of nitrogen and phosphorus recovery.